The invention is in the field of photoflash lamp arrays.
Various photoflash arrays have been proposed, and at least one type is now commercially available, containing a plurality of flash lamps. The arrays are provided with terminals for connecting the lamps, or lamp sequencing circuitry in the array, to a camera socket which provides a firing pulse (in synchronism with opening of the camera shutter) to the array for flashing a flash lamp when a flash picture is desired. Several flash pictures may be taken without moving or removing the array. A type of flash array having multiple connector terminals for connecting the flash lamps to a firing circuit in a camera is disclosed in U.S. Pat. Nos. 3,598,984 to Stanley Slomski and 3,598,985 to John Harnden and William Kornrumpf, and a type of flash array containing sequential lamp flashing circuitry and thus requiring only two connector terminals for connecting the array to a source of firing voltage pulses is disclosed in U.S. Pat. Nos. 3,532,931 to Paul Cote' and 3,668,421 to Harry Bowers. Some of the just-referenced patents also disclose dual-sided arrays having a first group of lamps at the front of the array and a second group of lamps at the back of the array. The array is plugged into a camera with one of the groups of lamps facing frontwardly, and when these lamps have been flashed, the array is turned around and the lamps of the other group are flashed.
The flash lamps in an array may be a low-voltage type requiring a voltage pulse of about 3 volts to 15 volts, for example, or may be a high-voltage type requiring, for example, a firing pulse of about 100 to 2000 volts or more or low energy. An example of a high-voltage flash lamp and a piezoelectric firing pulse source which produces a firing pulse when a piezoelectric element is impacted in synchronism with the opening of a camera shutter is disclosed in U.S. Pat. Nos. 2,972,937 and 3,106,080 to C. G. Suits. Flash arrays, and particularly if they employ high-voltage types of flash lamps which are flashed by a high-voltage pulse of low energy, are prone to accidental electrostatic firing of one or more lamps if a connection terminal of the array is touched by a person or object having an electrostatic charge. Also, in a dual-sided array, there is a possibility of accidentally flashing a lamp in the back group by induced voltage when a lamp in the front group is flashed.